The present invention relates generally to yarn changing devices for flat bed knitting machines. More particularly, yarn guide collar support racks are provided on opposite ends of the knitting bed to hold yarn to be knitted. The yarn changing device is adapted to pick yarn guide collars held at either end of the knitting machine.
Flat bed knitting machines are generally well known. For example, U.S. Pat. No. 3,911,700 discloses a knitting machine having a storage rack on one side of the knitting machine. A plurality of yarn guide collars are detachably held within the storage rack. A carriage is provided on the main body of the knitting machine. The carriage is arranged to move back and forth along a needle bed and has a yarn changing device thereon. The yarn changing device is capable of picking collars from the storage rack at one end of the needle bed and includes a collar support member arranged to hold a selected collar. In order to change yarns during the knitting operation, the carriage moves to the end of the needle bed adjacent the collar supporting device. The particular collar holding the desired yarn is then exchanged for the collar currently held by the carriage. In this manner, patterns having multiple colors can be knitted by changing the yarns used during the knitting operation. Although such devices are capable of knitting fabric having multiple colors, they have certain undesirable limitations. For example, since the collar supporting device is located at only one end of the needle bed, every time a yarn change is desired, the carriage must travel to the yarn changing end of the needle bed.
U.S. Pat. No. 4,111,007 discloses a yarn changing device for flat-bed knitting machines having an alternative construction. However, like the previously described patent, it contemplates changing the active yarns at only one end of the needle bed. U.S. Pat. No. 4,354,363 discloses a controller for directing the movements of a carriage along the needle bed of a flat bed knitting machine.